Valve membrane



FIG. 1 is a front top perspective view of a valve membrane according to our design;

FIG. 2 is a front bottom perspective view thereof;

FIG. 3 is a front elevational view thereof, the rear elevational view being a mirror image thereof;

FIG. 4 is a right side elevational view thereof, the left side elevational view being a mirror image thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines shown in the drawings are for the purpose of illustrating environmental structure and form no part of the claimed design. 

CLAIM The ornamental design for a valve membrane, as shown and described. 